电子元器件贮存可靠性评估与预测的贝叶斯方法

基于电子元件寿命试验的二项型数据信息,提出了电子元件贮存可靠性评估与预测的贝叶斯方法.利用环境因子将电子元件产品在不同贮存条件下的试验数据进行折合,依据贝叶斯理论对小样本下可能出现的数据"数据倒挂"进行预处理,并评估出其在各已知贮存时间点上的可靠度,再运用配曲线法得到产品的贮存寿命分布,进而对其贮存可靠度进行合理预测.最后,通过一个实例说明了方法的可行性.     

Reliability estimation of aeronautic component by accelerated tests

This article presents a reliability assessment of aeronautic electronic board using the accelerated test approach. The mission profile used is one defined in FIDES for electronic equipment in aircraft. The reliability function is defined taking into account the different phases of product life (Ground, Taxiing, Flying, Dormant). FIDES describes the environment (thermal and humidity, thermal cycling, mechanical, …) for each phase. The paper presents the different accelerated life models used to take into account all environment. A test plan is proposed to estimate the unknown parameters of accelerated life models. The thermal and humidity and thermal cycling tests have been performed and the data are analyzed. Finally, the reliability function is evaluated.     

Model-based reliability analysis

Testing has typically been a key means of detecting anomalous performance and of providing a foundation for estimating reliability for weapon systems. The objective of model-based reliability analysis (MBRA) is to identify ways to capitalize on the insights gained from physical-response modeling both to supplement the information obtained from testing and to better-understand test results. Five general MBRA processes are identified which can capitalize on physical response modeling results to make both quantitative and qualitative statements about product reliability. A case study that explores 1 of these 5 processes was completed and is described in detail. It had the benefits: MBRA can be used to determine a performance baseline against which current and future test results can be compared; during the design process, MBRA can provide tradeoff studies such that development time and required test assets can be reduced; MBRA can be used to evaluate the impact of production and part changes, as well as aging degradation, if they arise during the product life cycle; and MBRA lays the foundation to evaluate anomalies that are observed in a test program. Typically it has been challenging to determine how anomalous behavior can manifest itself under different-but still valid-conditions. One can use modeling to inject hypothesized behaviors under different conditions and observe the consequences     

Software reliability measurement

The measurement and analysis aspects of software reliability are described with the aim of providing software engineers and managers a sense of where and how software reliability measurements can be applied to their projects. Some background for understanding software reliability measurement is provided, and activities associated with measuring and analyzing software reliability are discussed in the context of the software product life cycle. The focus is on failures and the rate at which they occur. The thrust of reliability measurement and analysis is to specify what the customer needs in terms of reliability before a software product is built, to validate that these needs are met before delivery of the product to the customer, and to make sure that the customer's needs continue to be met after delivery     

Robust Electromigration reliability through engineering optimization

With complex process integration approach and severe fabrication limitations caused by introduction of new materials and diminishing process margins, there are mounting concerns with the increased failure rate at the early life cycle (e.g.<1 year operation) of product application known as infant mortality failures. A paradigm change in reliability qualification methodology aim at understanding the impact of variation on reliability is required to ensure reliability robustness. Using Electromigration (EM) as an example, this paper described a methodology where the impact of process variation on reliability is studied. A model that predicts the impact of process variation on EM sigma is also proposed which enables variation and its impact on reliability to be quantified. Using this methodology, the critical process parameters impacting reliability could be identified and controlled to ensure reliability robustness.     

软件产品保证--系统策划与分阶段任务

软件产品保证是产品保证的重要组成部分，较详细地阐明了软件产品保证的策划过程，系统地归纳了软件研制各阶段的软件产品保证活动，对软件开发人员和质量管理人员有一定的指导作用。     

Engineering Reliability Management

This paper describes various areas of the reliability management. Areas covered are the historical development, general management considerations, achieving the reliability program objectives and guidelines for the reliability program management, reliability and maintainability management tasks in the product life cycle, steps to improve reliability of engineering products, reliability and maintainability departments, reliability manpower, documents and tools for reliability management, reliability auditing and pitfalls in reliability program management.     

基于ath5k网卡驱动实现的车载网IEEE802.11p协议的研究

IEEE802.11p协议标准主要用于车载网络通信,有利于推动智能交通系统的实现,因此在实际交通环境下对IEEE802.1 1p协议进行研究具有重要意义.通过修改OpenWrt路由操作系统的ath5k网卡驱动实现了IEEE802.11p协议标准,并移植到Mikrotik RouterBoard433AH路由开发板上成功运行.在此基础上,对实际道路环境下IEEE802.11p协议和IEEE802.11a协议的发送速率、丢包率等网络性能参数进行了研究测量比较.实验数据显示在多障碍物、情况复杂的实际道路环境,IEEE802.11p协议更能满足通信可靠性和有效性的要求.     

电子式电能表单板老化的实现

电子式电能表要求有较高的质量稳定性和可靠性,而质量稳定性和可靠性却受制造工艺和电子器件的质量寿命影响。为了达到提前暴露电子器件的质量缺陷和延长其寿命并且不影响大批量生产周期的目的,同时降低成本投入,保证高效率,在此提出采用高温单板老化工艺来提高电能表的稳定性和可靠性。实验结果表明,该方式能够使产品现场运行稳定可靠。     

Competing causes of failure and reliability tests for Weibull lifetimes under type I progressive censoring

For many high reliability products where very few items are expected to fail during the test period, testing under normal conditions is not feasible. Further, the requirement for high reliability increases the need for test procedures which yield valuable degradation and other useful information for improving product reliability. Thus in some manufacturing and other experiments, various types of failure censored and accelerated life tests are commonly employed for life testing. In this paper we discuss Type I progressively censored variable-sampling plans for Weibull lifetime distributions under competing causes of failure. The proposed procedure is attractive as it yields useful degradation-related information for improving product quality. In addition, the procedure is useful when a test is conducted under severe time constraint and/or when the experimenter wishes to save costly specimens or scarce test facilities for other use.     

Plastic Ball Grid Array Solder Joint Reliability for Avionics Applications

The solder-joint reliability of plastic ball grid array (PBGA) packages for an avionics application was assessed. The fatigue life under combined temperature cycling and random vibration conditions was initially simulated using analytical models. Further simulation was used to plan an accelerated test and to estimate an acceleration factor between field conditions and test conditions, and experimentally verified. The combination of simulation and experimental results was then used to reassess the solder-joint reliability under field conditions. Based on the simulation and test results, it was estimated that PBGA packages without underfill would not satisfy the long-term life expectation for the avionics application under study. In addition, the experimental results also show that the simple application of linear damage superposition (Miner's rule), which neglects the interactions between loads, will underestimate the damage and overpredict the product life. Therefore, calculating the acceleration factor is necessary and cost-efficient for providing the basis of product field reliability assessment     

Product Reliability and Random Fatigue

The fatigue life of a mechanical component in a conventional ional test situation depends upon the stress amplitude. A change in the stress amplitude during a laboratory test-program involves a consideration of the damage produced by each stress cycle imposed upon the test specimen. A direct extension of this elementary concept to irregular stress waveforms provides a logical basis for a statistical analysis of product reliability due to random fatigue. The statistical behavior of the fatigue life is related to the probability distribution of the maxima and minima in a random stress waveform. The fundamental relation between the probability of survival and the maxima-minima is derived in this presentation, which contains a theoretical application to a simple random stress oscillation. The same expression may be used in the development of a computer program to evaluate product reliability from a numerical analysis of experimental data.     

Optimum design of reliable systems for specified life cycle cost

A new procedure for design for optimum reliability is given using a maximum life cycle cost constraint. Various life cycle cost vs reliability models are used for the purpose. The problem is treated for a series reliability structure. A numerical example is given to illustrate the procedure. The work establishes a firm quantitative footing for optimum life cycle cost design of reliable systems. In a sense it is revolutionary in the design-to-cost philosophy so often encountered in reliability design.     

Reliability Modeling in Spatially Distributed Logistics Systems

This article proposes methods for modeling service reliability in a supply chain. The logistics system in a supply chain typically consists of thousands of retail stores along with multiple distribution centers (DC). Products are transported between DC & stores through multiple routes. The service reliability depends on DC location layouts, distances from DC to stores, time requirements for product replenishing at stores, DC's capability for supporting store demands, and the connectivity of transportation routes. Contingent events such as labor disputes, bad weather, road conditions, traffic situations, and even terrorist threats can have great impacts on a system's reliability. Given the large number of store locations & multiple combinations of routing schemes, this article applies an approximation technique for developing first-cut reliability analysis models. The approximation relies on multi-level spatial models to characterize patterns of store locations & demands. These models support several types of reliability evaluation of the logistics system under different probability scenarios & contingency situations. Examples with data taken from a large-scale logistics system of an automobile company illustrate the importance of studying supply-chain system reliability.     

航天器产品可靠性指标验证方法探究

对于受到多方条件限制的航天器产品而言,在交付验收阶段和型号出厂前,需要开展可靠性验证工作.航天器产品可靠性定量要求(指标)的验证可以选用多种方法进行.结合光学载荷产品可靠性指标验证的工作经验,提出了一种充分利用产品寿命周期各阶段的可靠性信息,采用贝叶斯法进行可靠性评估的方法.试验证明,这是一种经济、有效和可行的方法.     

部分气候防护场所产品可靠性试验周期研究

针对安装在有部分气候防护场所的产品,研究总结其使用特点,对其工作条件、环境条件及其严酷度水平进行分析,设计合理的可靠性试验周期,以充分暴露该类产品的质量缺陷并科学评价其可靠性水平。     

An automated field repair tracking system [telecommunicationproducts]

The purpose of repair tracking (RT) is to provide ongoing feedback of product reliability performance in the customer environment. The authors present an RT technique and provide an overview of its automated software implementation, which has been used to track several transmission system products. The RT implementation, referred to as the repair equipment analysis program (REAP), tracks the field performance of electronic equipment at system, subsystem, circuit pack, and component levels. The features of REAP include monthly reliability performance reports, alarms when degradation in performance is detected, model sensitivity analysis, problem areas isolation for initiating corrective actions, and specific customer performance studies. The approach encompasses the entire population during the product life using existing sales and repair data as main inputs. Further, it does not require customer involvement or product serialization     

定量可靠性

定量可靠性是今后的趋势和方向,对于现在非常流行的高加速寿命试验我们现在可以对其进行定量分析,这是一个突破性的进展,它会帮助我们在研发阶段就建立起定量可靠性的数据,从而更好的保证产品的可靠性并控制成本。     

Educational needs for reliability and maintainability

Because of the scope and inter-disciplinary nature of the subject, reliability education provides special problems. The kinds of tasks and therefore the training needs of reliability staff are highly dependent on the role of the organization in the equipment life cycle and to a lesser degree, the nature of the product. Correctable short-comings in available reliabiliy education include lack of instruction in environmental engineering, parts control, documentation. Program management and personal communication techniques are also recommended.